Stabilization of a rocky wall using the self-drilling bar system


The intervention was carried out on a rocky slope located east of the village of Rovetta (BG) in an unsafe area located right next to some existing houses. It was therefore necessary first to carry out the stabilization of the friable rocky surface layers.
The surface area was first cleared and then a passive anchoring system with self-drilling bars was implemented. This anchoring system is a technique that consists in inserting a hollow section steel bar into the ground, equipped with a disposable drill bit. The self-drilling bar is inserted into the ground using a special rotary-percussion drill and using pressure-injected cement grout as drilling fluid. The installation of the anchor can be considered performed when the tip reaches the project depth, without requiring further processing.

The intervention area can only be accessed from the valley through a narrow rocky inlet so it was necessary to access with an extremely small vehicle: the small and light Spider excavator Kamo 35 belonging to Impresa Duci fleet was set up with sled and drill, in order to be able to carry out this special task.

For this special work, DYWI® self-drilling bars D.32 mm were used, length 4.00 mt.
The safety intervention was then completed with the construction of a reinforced concrete wall anchored witth plates.

1. Drilling Adapter with Grout Bottle for Grouting
2. DYWI® Drill Hollow Bar
3. Cement Mortar
4. Coupler
5. Retroflushing for Stabilization and Load Transfer
6. Drill Bit.